What is "big girl's blouse"

n. (context idiomatic English) An effeminate or weak man, a sissy.

Big Girl's Blouse is an Australian skit program that aired in the mid-1990s on the Seven Network. The show was created by Gina Riley, Jane Turner and Magda Szubanski who all went on to star in Kath & Kim. There were four one-hour episodes, plus the pilot, which are usually shown as eight half-hour episodes. The phrase "Big Girl's Blouse" is a British English idiom meaning "ineffectual or weak, someone failing to show masculine strength or determination".